1. Field of the Invention
This invention concerns a vegetation body in the form of sheeting with a structured mat in particular a looped mat.
2. The Prior Art
Such vegetation bodies in the form of sheeting are known from European Patent No. 172,839 B1 and German Patent No. 4,219,275 C2, for example. These and similar vegetation bodies in the form of sheeting are used in particular for roof sodding. To sod a flat or pitched roof with such mats, the vegetation bodies are laid side by side on the roof, with the vegetation bodies being laid as sheeting with end-to-end butt joints. The vegetation bodies are either laid directly on the roof surface or on a substrate layer applied to the roof. Before laying the sheeting on the roof, the vegetation bodies in the form of sheeting are usually precultivated, i.e., before being installed on the roof, the vegetation bodies are filled with substrate and vegetation material capable of germinating. Plant seeds, sprouts of sedum species and moss spores in particular have proven suitable as the vegetation material capable of germinating.
The structured mats of such vegetation bodies serve to provide a hold and cohesion for the substrate material and the plant parts. The porous substrate arranged beneath the structured mat, usually made of coconut fibers, rock wool, textile fibers or suitable materials, serves to store water, provide drainage and a hold for the roots of the plants and as a dividing layer for particles that can be washed away.
The vegetation bodies known in the past have proven largely successful. However, it has been found that due to prolonged dry periods in particular, the vegetation bodies laid with butt seams begin to shrink, causing gaps to form between the individual sheets. These gaps not only interfere with the visual impression but also are also subject to the risk that wind forces can act on the bottom sides of the vegetation bodies, causing the vegetation bodies to be lifted due to suction, at least partially destroying the roof sodding. If substrate material is laid under the vegetation body, the substrate material may also be eroded due to wind effects through the shrink holes.
German Patent No. 3,815,662 A1 describes a two-dimensional structural part for use in gardening, having at least two independently structured layers, at least one of which has a self-supporting structure. The bottom layer is formed by a drainage plate with the vegetation plate on top of it as the top layer made mostly of natural organic material. The two layers are joined together to form a dimensionally stable structural part representing a unit. Both layers are designed as rectangles with essentially the same length and width dimensions, with the vegetation plate as the top layer being arranged with a translational offset with respect to the bottom drainage plate.
The offset between the vegetation plate and the drainage plate should yield the result that no continuous troughs can be formed between adjacent structural parts from the vegetation substrate applied subsequently to the vegetation plate to a flat roof on which the two-dimensional structural part is laid. With the known two-dimensional structural part, the offset is provided between the complete vegetation plate equipped with the vegetation substrate on the one hand and the drainage plate beneath it on the other hand, and since the vegetation plates themselves abut against one another without any offset, the shrinkage gaps mentioned above also cannot be avoided with this two-dimensional structural part.